Design of high-contrast all-optical bistable switches based on coupled nonlinear photonic crystal microcavities

We present a bistable photonic crystal configuration consisting of a waveguide directly coupled to three microcavities with instantaneous Kerr nonlinearity. Coupled mode theory combined with a numerical simulation based on the finite-difference time-domain technique is employed to design and evaluate the optical configuration. We demonstrate that with the proper choice of resonant frequencies of the constitutional photonic crystal microcavities, such a configuration can function as a high contrast switch, and the contrast between the bistable states in its transmission can be as high as 300. We expect this device to be useful in the practical application of all-optical switches. (C) 2011 American Institute of Physics. [doi:10.1063/1.3580266]